Ranunculaceae
Actaea racemosa
Black cohosh · Black snakeroot
- Part used
- rhizomeroot
- Native range
- Eastern North America
- Morphology
- A woodland perennial to two and a half metres with large divided leaves and long slender spires of small white flowers with a strong, unpleasant smell.
- Also known as
- Cimicifuga racemosa
What is in it
Evidence
Trials for menopausal hot flushes are inconsistent. Cochrane found insufficient evidence of benefit; some individual trials and the German standardised preparations report modest effects. The mechanism is not oestrogenic, contrary to how it is usually marketed.
Safety
Liver injury is the significant concern. Case reports of hepatitis and liver failure led the TGA, the EMA and the MHRA all to require warning statements, and Australia mandates one on every product. The relationship is not firmly established and some cases involved adulterated material, which is itself part of the problem.
Interactions: Additive liver risk; Unclear interaction with tamoxifen and hormone therapy
Regulatory: Permitted in Australia with a mandatory liver warning on the label.
Historical use
Used by Cherokee, Iroquois and Algonquian peoples for rheumatism and for gynaecological complaints. Taken up by the Eclectics and then commercially in Germany from the 1950s for menopausal symptoms.
Recorded as history and attributed where possible. Long use establishes that a plant was widely used, not that it worked, and not that it was safe.
Worth knowing
Black cohosh is a genus-change case that matters commercially: it was Cimicifuga racemosa for most of its documented history and is now Actaea racemosa, so a century of literature is filed under a name the current authorities treat as a synonym.
The adulteration angle is worse than the taxonomy. Several Asian Actaea species are cheaper and have been repeatedly found substituted in retail products — a 2012 study using DNA barcoding found a substantial proportion of black cohosh supplements contained Chinese Actaea species instead. Since the liver injury signal is what regulators are worried about, and nobody knows which species the implicated products actually contained, the safety question cannot be cleanly answered.
Nomenclature verified against GBIF backbone taxonomy.